Call it the Caucus Mythbusters edition of the Iowa Poll. It’s a good time to review some of the conventional wisdom, truisms and theories about the Iowa caucus campaign and see how they are holding up.

Here’s a few statements that you’ve probably heard about the caucus race at one time or another (some of them from me), and what the Register’s poll of likely Iowa caucusgoers has to say.

Myth — Newt Gingrich is toast: Gingrich, in Des Moines on Thursday, joked: “As most of you know, I was, in June, July, dead. So it’s great to be back.” Gingrich holds a solid lead with 25 percent in the new poll, up from 7 percent in October. Now, the guy who was thought to have too much personal baggage is the first choice of caucusgoers who describe themselves as “very conservative.” The guy who was too much of a Washington insider is winning with Tea Partiers.

Four years ago, Mike Huckabee first took the lead in the Iowa Poll in late November and went on to win the caucuses. So this seems like an opportune time for Gingrich to stage his revival. But success can be even more fleeting this election cycle. It remains to be seen whether he can survive the inevitable pummeling that will come his way, ace the two coming Iowa debates and put together an organization to deliver votes on caucus night. One truism about Iowa that still needs testing is how much the ground game matters.

Fact — Herman Cain is toast: But you knew that already, and so did Cain. The poll confirms that Gingrich is the primary beneficiary from Cain’s decision Saturday to suspend his campaign.

Myth — Iowa GOP wants anyone but Mitt Romney: Romney’s fallen below 20 percent for the first time in the Iowa Poll this cycle, but he’s still a contender for the caucuses. The former Massachusetts governor has largely avoided Iowa this cycle, but now he’s starting to advertise, bring in surrogates and raise his profile. Likely caucusgoers pick him as most electable in the general election (38 percent); most presidential (34 percent) and most likeable, 19 percent. He’s least-liked by 15 percent, tying with Michele Bachmann. The plurality of Gingrich and Ron Paul supporters pick Romney as their second choice.

Myth — Ron Paul can’t win: The Texas congressman’s support has risen slowly and steadily with each new Iowa Poll. He’s leading with young caucusgoers, independents, moderates and liberals, which isn’t terribly surprising. Paul is continuing to grow by bringing new people into the process. With new caucusgoers, he’s at 19 percent, just 1 point behind Gingrich. Likely caucusgoers consider him the most fiscally responsible, at 32 percent, and 24 percent say he’s the most principled. He has some challenges: 19 percent say he’s most negative, and he’s the second choice of only 7 percent. His Iowa campaign is more seasoned than Gingrich’s, but he’ll need that edge to deliver younger and less-experienced caucusgoers on Jan. 3.

Myth — Social conservatives dominate: On social issues like abortion and gay marriage, 46 percent of likely caucusgoers say they are very conservative, and 18 percent say they are mostly conservative. The favored candidates for this group are, in order: Gingrich, Paul and Romney. Michele Bachmann, who is at 8 percent in the poll, is considered the most socially conservative by 27 percent of caucusgoers, a plurality.

Myth — Rick Santorum’s time is coming: Conservatives have kept talking up the chances of the former Pennsylvania senator, who has spent more time in the state than any other candidate. He’s just not a factor, and there’s not much time left.

Stay tuned — Grassroots rule: Thirty-five percent of likely caucusgoers have seen at least one candidate in person so far. That’s higher than in late December 2007, when 31 percent had seen at least one candidate, even though the Republicans have spent fewer days in the state this year. The question is whether the personal touch still matters. Bachmann has had the most in-person exposure to caucusgoers, with 20 percent saying they’ve seen her. Paul is second at 15 percent. Of the candidates campaigning in Iowa, only Perry is in single digits.